Metric bolts for ANSI flanges 2

[edemarcos]

Problem : Use metric bolt on ANSI flanges.
There are reference codes or rules to have the exact change ?

Many thanks in advance.

 

[MortenA]

There are no "metric bolts" but there are e.g. DIN flanges (German norms). Anyway MGP has answered this part (ANSI/DIN differences( on several occations).

You could check this tread - where he even posts a spreadsheet that may help:

http://www.eng-tips.com/viewthread.cfm?qid=83452

Best regards

Morten

 

[MortenA]

The refereced thread may not be the best for your question - but try to make a searc here on eng-tips and use the "Threads by handle" and search for the MGP handle.

Best regards

Morten

 

[edemarcos]

Sorry, but my problem is to use a metric bolt ( M20, M30 and so on ) with B16.5 Flange.

For example what metric bolt I must use for DN24'' 150#.
B16.5 gives only Bolt hole diameter and not Bolt size.
From manufacturers catalogs I have 1-1/4'' ( quite 31.75 mm ), but from bolt tables I have M30 or M33, so I don't know what is the correct metric size.

There is a code or section of code that gives this information ? Or I must verify the flanged joint according to ASME VIII - Div 1 appendix 2 ?

Many thanks in advance

 

[CRG]

edemarcos, 1996, B16.5 gives both bolt hole size and bolt size (1.38” and 1.25” respectively). I am at home and do not have the 2003 B16.5 here; however, I don’t think that they removed the bolt size data in the current version.

You can use any size bolt you want in these flanges; however, you may find a problem with code compliance in your jurisdiction. If you want to use metric bolts for a flange designed for bolts manufactured for the inch system, calculate the bolt loading and select the appropriate sized bolt and material. Again, this may not meet your code requirements.

What code, if any, are you using for a design guideline?

 

[edemarcos]

Thanks CRG.
I have checked, and what you say is right : in the table named "Template for drilling class .. " B16.5 1996 gives hole and bolt size.
The problem is that the bolt size is in inch units only.

For design guideline I use ASME VIII div.1, but my customer requires to use metric bolts instead of standard bolts ( inch units ).
So my problem is to choose the metric bolt that is equivalent to standard bolt.
For small flanges the difference in diameter between metric and inch bolt is quite negligible, but not for large flanges.

This morning, from internet, I have read that there is a new edition of B16.5 that give metric and inch bolts.
It is correct ?

Many thanks for Your help.

 

[DVNMech]

Hello edemarcos,

For your problem, you can look in the preliminary standard prEN1759-1 Annex F. This standard describes the use of ANSI flanges Europe. Annex F gives equivalent bolt sizes, compared with the ANSI bolts. I've added the list for you.
Boltsize Inch Metric
1/2 M14
5/8 M16
3/4 M20
7/8 M24
1 M27
1 1/8 M30
1 1/4 M33
1 1/2 M39

Higher sizes are not mentioned.

Hope this helps you

Kind regards

 

[KeithDouglas]

I am presently working on a project in Kazakhstan where we are using metric bolts for ANSI flanges, the project piping specification that we are using gives the following imperial to metric conversions.

Bolt Dia Inch Metric
5/8" M16
3/4" M20
7/8" M24
1" M27
1 1/8" M30
1 1/4" M33
1 3/8" M36
1 1/2" M39
1 5/8" M42
1 3/4" M45
1 7/8" M48
2" M52
2 1/4" M56
2 1/2" M64
2 3/4" M72
3" M76
3 1/2" M90

Hope this helps'
Regards.